氯霉素免疫抗原及包被抗原的制备

采用混合酸酐法合成30:1～10:1 三个不同起始物质的量比的氯霉素免疫抗原(HAP-KLH),采用活泼酯法(EDC-NHS)合成40:1～1:1 七个不同起始物质的量比的包被抗原(HAP-OVA),紫外测定HAP-KLH 偶联比25:1～8:1,HAP-OVA 偶联比23:1～1:3。间接竞争ELISA 实验优化包被抗原,在23:1～3:1 偶联比范围内,氯霉素(CAP) IC50值为36～15ng/mL,随着偶联比的减小而降低,当偶联比低于3:1 则略为上升。确定了包被抗原HAP-OVA 最佳偶联比为3:1。本研究表明包被抗原的偶联比对ELISA 测定IC50 值有重要影响,应合成不同偶联比的包被抗原,选出最佳偶联比。     

抗莱克多巴胺单克隆抗体杂交瘤细胞株的建立及其免疫学特性鉴定

莱克多巴胺(RAC)经化学修饰引入功能基团羧基,合成半抗原RAC- 戊二酸酐半醛化合物(RAC-SA),用混合酸酐法(MA)将RAC-SA 偶联于牛血清白蛋白(BSA),合成人工抗原BSA-RAC,用红外(IR)、紫外(UV)和凝胶电泳(SDS-PAGE)对其进行鉴定;用BSA-RAC免疫Balb/C 小鼠,细胞融合技术建立抗RAC的单克隆抗体(RAC mAb)杂交瘤细胞株,体内诱生腹水法制备RAC mAb,并鉴定其免疫学特性。结果表明,BSA-RAC 偶联成功,偶联率为24.5:1;筛选出3F10、3H12、4D8 共3 株杂交瘤细胞,其中最好的4D8 株间接ELISA 效价细胞培养上清为1:1.28 × 103,腹水为1:6.4 × 105,同种型为IgG1/κ,亲和常数(Ka)为1.65 × 1010L/mol,对RAC 的半数抑制浓度(IC50)为5.7ng/ml,与多巴酚丁胺的交叉反应率(CR)为22.3%,与其他化合物无CR。     

有机磷农药三唑磷单克隆抗体制备及鉴定

采用活泼酯法和混合酸酐法将三唑磷半抗原(TZPM-Hap)与牛血清蛋白(BSA)和卵血清蛋白(OVA)偶联,分别制备出一种免疫抗原(TZPM-A-BSA)和两种包被抗原(TZPM-A-OVA和TZPM-M-OVA)。通过免疫小鼠及细胞融合,并对杂交瘤细胞进行经多次筛选和亚克隆得到1株产三唑磷单克隆抗体阳性细胞株(FC3),其抗体亚类为IgM。辛酸-硫酸铵沉淀法纯化后的抗体经间接ELISA检测,该方法IC50=9.7μg/L,最低检测限(LOD)为1.0μg/L,定量检测线性范围(IC20～IC80)为2.5～100.0μg/L,与其他有机磷农药结构类似物无明显交叉反应,显示出高度的特异性。该抗体可进一步用于免疫分析试剂盒开发。     

杀菌剂抑霉唑人工抗原的合成和鉴定

以咪唑乙醇为原料,与6- 溴己酸乙酯发生取代反应后再经水解反应合成抑霉唑半抗原(6-[1-(2,4- 二氯苯基)-2-(1- 咪唑基)乙氧基]己酸)。产物经薄层层析和1H-NMR 鉴定后,采用活化酯法分别与牛血清蛋白(BSA)和卵清白蛋白(OVA)偶联得到免疫原(HIA-BSA)和包被原(HIA-OVA),紫外光谱分析法计算得其偶联比分别为13:1 和7:1,初步说明人工抗原合成成功。通过免疫动物获得效价为1:64000 的抗体,采用间接竞争ELISA 法测定抗体的IC50 值为1.76μg/mL,从而进一步证明人工抗原合成成功,所得的抗体可用于ELISA 检测试剂盒的研制。     

盐酸西布曲明人工抗原的合成与鉴定

目的：建立盐酸西布曲明的免疫分析方法。方法：4-氯苯乙腈和1, 3-二溴丙烷为原料合成与盐酸西布曲明具有相同母核结构的小分子双去甲基西布曲明(M2),以双去甲基西布曲明为半抗原,并分别通过活泼酯法、戊二醛法和混合酸酐法将半抗原与牛血清白蛋白(BSA)和卵清蛋白(OVA)偶联制备免疫原(M2-BSA)和包被抗原(M2-OVA)。结果：紫外光谱扫描证明半抗原M2与载体蛋白偶联比为24.6:1(M2-BSA)和16.2:1(M2-OVA),抗血清ELISA效价均达到1:8000以上,IC50=0.42μg/mL。结论：半抗原M2与载体蛋白均已成功偶联,其中活泼酯法对半抗原活性基团的影响最小,合成人工抗原的特异性最强。     

对氯甲基苯甲酸链接的莱克多巴胺人工抗原的合成与鉴定

采用对氯甲基苯甲酸(CBA)为链接臂,用混合酸酐法将莱克多巴胺(RAC)与牛血清白蛋白(BSA)偶联制备人工抗原(RAC-CBA-BSA),通过紫外、红外、电泳鉴定抗原合成成功;再以卵清蛋白(OVA)为载体蛋白合成包被抗原(RAC-CBA-OVA),测定其与抗体的亲和力和抑制率。间接竞争ELISA结果以对CBA为链接臂合成的包被抗原对应的抗体滴度为7047.3、IC50为17.05ng/mL,结果表明,CBA可以用于RAC人工抗原的合成,使用RAC-CBA-OVA作为包被抗原可以提高ELISA检测灵敏度。     

三聚氰胺单克隆抗体的制备及鉴定

为建立三聚氰胺免疫分析方法,采用戊二醛法合成免疫抗原MEL-BSA和包被抗原MEL-OVA,全抗原经紫外吸收法检测证实偶联成功且偶联比约为16∶1。用MEL-BSA免疫BALB/c小鼠,用常规单克隆制备技术筛选获得1株稳定分泌抗三聚氰胺单克隆抗体的细胞株6E3。腹水经纯化后,研究了抗体效价、竞争抑制能力及与结构类似物的交叉反应率,其中抗体效价为1∶64 000,检测线性范围为0.1~3.2 mg/L,IC50为1.01 mg/L,与三聚氰酸、三聚氰酸一酰胺及三聚氰酸二酰胺的交叉反应率均小于0.1%,该方法有望用于三聚氰胺免疫检测试剂的研制开发。     

莱克多巴胺和土霉素人工抗原的合成及鉴定

研究莱克多巴胺和土霉素免疫抗原的制备。实验中用碳二亚胺法将莱克多巴胺(ractopamine,RAC)与载体蛋白牛血清白蛋白(bovine serum albumin,BSA)偶联,制备完全抗原;采用混合酸酐法将土霉素(oxytetracycline,OTC)与载体蛋白BSA偶联,制备完全抗原,并对合成产物进行表征。紫外扫描对合成产物RAC-BSA、OTC-BSA进行鉴定结果显示偶联成功,经重氮化后利用混合酸酐法制备完全抗原的偶联比为5:1;经衍生后利用碳二亚胺法制备RAC完全抗原偶联比为7:1。利用制备的免疫原免疫兔子可以获得相应的抗体。     

呋喃唑酮人工抗原的制备与鉴定

为了制备3-氨基-2-恶唑烷酮(AOZ)的完全抗原,作者以乙醇肼和碳酸二甲酯为原料,首先合成了3-氨基-2-恶唑烷酮(AOZ),然后通过对醛基苯甲酸对AOZ进行衍生制得3-(4-羧基苯亚甲基)-氨基-2-恶唑烷酮(CPAOZ),以CPAOZ作为半抗原,经水溶性碳化二亚胺法(EDC),缩合酯化法(DCC)和混合酸酐法(MA)法3种方法分别与载体蛋白偶联,合成人工抗原。对于制备产物通过紫外光谱扫描分析进行了鉴定,3种抗原的偶联比率分别为8、12、17。采用3种抗原做为包被原,建立了酶联免疫(ELISA)抑制曲线。结果表明,对AOZ的半数抑制率(IC50)分别为12.9、7.6、1.1 ng/mL。采用混合酸酐法(MA法)制备的包被抗原与抗体具有较好的匹配性。3-氨基-2-恶唑烷酮(AOZ),是硝基呋喃类抗生素呋喃唑酮在动物体内的稳定代谢物,采用本试验制备的抗原,有望获得特异性更好的抗体。     

链格孢霉毒素细交链格孢菌酮酸人工抗原的合成及其多克隆抗体制备

本研究采用肟化法用羧甲基羟胺半盐酸盐对链格孢霉毒素细交链格孢菌酮酸(Tenuaconic acid,TA)进行衍生后引入连接臂,得到了半抗原TAO。通过活性酯法将半抗原TAO分别与牛血清蛋白(Bovine serum albumin,BSA)偶联制备得到免疫原TAO-BSA、与血蓝蛋白(Keyhole Limpet Hemocyanin,KLH)偶联制备得到包被原TAO-KLH。经透析纯化后分别采用紫外光谱、红外光谱扫描法对合成的人工抗原进行初步鉴定,制备得到的人工抗原的偶联比分别为18.3:1、38.7:1。此人工抗原免疫Balb/c小鼠后获得的鼠源抗血清进一步验证了人工抗原合成成功,制备得到特异性识别TA的多克隆抗体。通过ELISA棋盘法确定了最佳包被原浓度以及最佳抗体稀释度并建立了TA间接竞争ELISA检测方法,其灵敏度以半抑制浓度IC50表示为335.55 ng/m L,最低检出限(LOD)为19.00 ng/m L,定量线性检测范围为200.00~1563.00 ng/m L。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status